Problem: Kevin ate 1 slice of cake. Emily ate 1 slice. If Kevin ate $\dfrac{1}{7}$ of the cake, what fraction of the cake is remaining?
Answer: If 1 slice represents $\dfrac{1}{7}$ of the cake, there must have been a total of 7 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 2 slices, which leaves 5 out of 7 slices remaining. There is $\dfrac{5}{7}$ of the cake remaining.